DIfferential Durability -

Depends on what power you are putting though it. I've only heard of a couple of zapped diffs, but nothing rampant.

I toasted a stock diff with 4 psi of boost from a jrsc.

All depends on teh year/powertrian of the car.

PZEV 2.3 Duratecs have beefed diff spider gears...

Best bet is an aftermarket diff like the Quaife, Torsen or a plate-style diff from Lentech.

Forget the plate style KAAZ unit. I had a deposit on one with Lentech for months until they found they couldn't quite get it reliable enough for production, and there were issues with standard transmission fluid that could only be corrected by using a fluid with a waxier content. I just switched to the Torsen, and McNews shipped the ATX to Lentech a few weeks ago for the install. I'm wondering how well it will work with my Level10 bullet-proof upgrade. I guess if Tom can push 500+ hp through his Lentech, then my measly 300+ would be peanuts in comparison. Even Chris & Len at Lentech feel the Torsen is a better unit than the KAAZ for most driving applications. The KAAZ would only beat it in staight drag use. I'm not familiar personally with the Quaiffe, but everyone on this site who has one seems to rave about it.